Traditional litter boxes are simply containers to hold granular absorbent material. Animals are then trained to urinate and defecate into this material. Such pet litter generally contains an absorbent to contain liquid and chemicals to control smell and neutralize animal waste products. Most modern litters form clumps of litter and waste when wet, to allow easier removal of soiled litter. To clean the litter box after waste accumulates, someone must manually sift through the soiled litter mixture and scoop the waste clumps out. This is a generally unpleasant, time-consuming chore that requires the person to handle foul-smelling waste, often while coming into contact with unsanitary dust and animal waste from the soiled litter.
Some pet litter boxes have been designed to separate pet waste from litter material. For example, a screen may be included to aid in the removal of soiled litter clumps. Additionally, there are stacked litter box designs that utilize a screen to filter out waste clumps as litter flows from one box into another.
Two issues remain with the use of pet litter systems. First, there is a need to minimize exposure to the dust and germs associated with the litter. Second, there is a need to rapidly and using minimal effort remove clumps from the litter.